Man and the industrialized world have continually wrought havoc on the natural environment and the public is consistently reminded of the undesirable sick effects of the unfettered discharge of industrial wastes and other forms of air, water and soil pollutants. While it is still unclear exactly how much irreparable damage has been done up to this point in time, it is evident that positive steps must be taken to reverse the direction in which today's society is going and every effort must be made to save and rehabilitate that which has been already damaged.
Soil pollution is a major problem which must be addressed in the very near future. Unbridled and thoughtlessly uncontrolled dumpings of solid, liquid and gaseous pollutants find their way into the soil and can remain there for years. Polycyclic hydrocarbons, a common class of chemicals discharged by industries everywhere, possess toxic, mutagenic and carcinogenic properties. Hydrocarbon solvents have been carelessly dumped into the soil for years and problematically remain there with nowhere else to go. Thousands of tons of toxic compounds are buried in the soil every year in high commercial landfills and these are scattered throughout the surrounding area for miles by rain and sub-surface ground water. Besides industrial and municipal wastes, pesticides, herbicides, and insecticides ultimately end up in the soil and, as they are not readily degradable, persist there for a long time.
Soil pollutants widely prevalent today are known as volatile organic contaminants which are organic compounds such as low molecular weight alkanes, alcohols, amines, amides, acids, sulfites, dioxins, ethylbenzenes and PCBs. Soil decontamination of these compounds as well as other pollutants has been achieved to a limited extent through solvent extraction, coagulation, high pressure cleaning, supercritical fluid extraction, thermal desorptions, soil vapor extraction, incineration and microbial oxidation. Physical means include pumping the ground soil with water followed by air stripping the soil to remove the volatile hydrocarbons, vacuum extraction and site excavations followed by incineration of the contaminated soil.
U.S. Pat. No. 5,453,133 (Sparks et al., Sep. 26, 1995) relates to a process for removing contaminants, such as hydrocarbons, from soil. The process involves contacting the contaminated soil with a suitable solvent for the contaminant, in the presence of a bridging liquid which is immiscible with the solvent, while agitating. The amount of the bridging liquid and the degree of agitation are balanced to control the particle size of the substantially contaminant- and solvent-free soil agglomerates so formed.
U.S. Pat. No. 5,611,642 (Wilson, Mar. 18, 1997) provides a method and apparatus for in-situ treatment of soil and ground water contaminated with organic pollutants. The process involves defining the nature and extent of the contamination; determining the hydrology and geology of the contaminated area; determining the volume and concentration of a reactive solution required to effect treatment of the contaminated area; injecting the reactive solution into one or more injectors that are inserted into the ground, sealed and positioned so as to assure flow of the reactive solution through the contaminated area; allowing the reactive solution to flow through the contaminated area thereby reacting chemically with the contaminants contained within the contaminated area; and determining when the treatment is complete by monitoring by-products of the chemical reaction. Preferably, the reactive solution is an aqueous solution of hydrogen peroxide and metallic salts.
U.S. Pat. No. 5,634,983 (Kammeraad, Jun. 3, 1997) relates to a process of soil remediation in which an encapsulation solution is introduced into contact with a soil matrix containing chemical contaminants such as polynucleated aromatics chloronated hydrocarbons and the like in an amount sufficient to form a saturated admixture of the soil matrix and the encapsulation solution, the encapsulation solution being capable of preferentially attracting the chemical contaminants contained in the soil matrix, and containing an effective amount of non-ionic surfactant material, an anionic suifactant material and water; and the admixture is admixed for an interval sufficient to permit the chemical contaminants to preferentially dissociate from contact with the soil matrix in favor of association with the encapsulation solution and at least one carbon bond in the chemical contaminant to be broken as a result of interaction between the non-ionic surfactant material and the contaminant. Once this occurs, a major portion of the encapsulation solution with associated chemical contaminants can be removed from contact with the soil matrix.
U.S. Pat. No. 5,725,470 (Lazarowitz et al., Mar. 10, 1998) discloses a process for the remediation of soil containing volatile organic compounds which comprises the steps of: (1) forming an emulsifier comprising: (a) from about 70 to about 99% by weight of a sugar surfactant selected from the group consisting of an alkyl polyglycoside, a glucamide, and mixtures thereof; and (b) from about 1 to about 30% by weight of a nonionic suifactant, other than said sugar surfactant which, when combined with said sugar surfactant, provides a hydrophilic-lipophilic balance of from about 8.0 to about 13.0; (2) mixing said emulsifier with said unwanted contaminants to form a stable emulsion; and (3) removing said stable emulsion from said soil.
U.S. Pat. No. 5,769,569 (Hosseini, Jun. 23, 1998) discloses an in-situ thermal desorption system and process is utilized for mobilization and removal of non-volatile and semi-volatile hydrocarbons from contaminated soil in the vadose zone. Persistent hydrocarbons are thermally desorbed by direct heating of the contaminated zone through combustion of fuel and air in a burner underneath the contaminated soil zone. The generated soil vapors are collected and treated by soil vapor extraction techniques.
U.S. Pat. No. 5,803,664 (Kawabata et al., Sep. 8, 1998) relates to a process for remedying a soil contaminated with a pollutant by using a microorganism, comprising the steps of:
injecting a liquid containing a microorganism capable ot degrading the pollutant into a predetermined site of the soil region to be remedied; and PA1 injecting gas into the predetermined site where the liquid agent is injected, wherein the gas injection step is conducted when a water content of the site is 0.6 or more times a saturation water content of the soil. PA1 contacting the contaminated soil with an aqueous composition comprising a surfactant of the structure ##STR1## PA1 wherein, Z comprises --R.sup.2 (O).sub.p SO.sub.3 M, --R.sup.2 COOM or ##STR2## PA1 and R.sup.1 is hydrogen or a hydrocarbyl group containing from 1 to 50 carbon atoms, R.sup.2 is a hydrocarbylene group containing from 1 to 22 carbon atoms, R.sup.3 and R.sup.4 are each independently hydrogen, a hydrocarbyl group, a hydroxyhydrocarbyl group, an alkoxyhydrocarbyl group wherein up to 12 carbon atoms are in the alkoxy group or an aminohydrocarbyl group, wherein the hydrocarbyl group contains from 1 to 22 carbon atoms, p is zero or 1, W is --SO.sub.3 M or --COOM and M is hydrogen, an alkali metal, an alkaline earth metal or +NR.sup.5 R.sup.6 R.sup.7 R.sup.8 wherein R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are independently hydrogen or hydrocarbyl groups containing from 1 to 22 carbon atoms, with the proviso that at least 9 carbon atoms are present in (I); PA1 1. Non-halogenated volatile organic compounds PA1 2. Halogenated volatile organic compounds PA1 3. Non-halogenated semi-volatile organic compounds PA1 4. Halogenated semi-volatile organic compounds PA1 5. Fuels
U.S. Pat. No. 5,834,540 (Katoot, Nov. 10, 1998) relates to a composition and process for the remediation of contaminated materials, and in particular for soil remediation. The reference relates to compositions and processes that cause the breakdown of unwanted contaminates, such as hydrocarbon wastes. The reference relates to the further use of radiation, preferably microwave radiation, to effect the degradation of contaminates. The reference is equally effective in treating materials that have been exposed to harmful or infectious biological contaminates.